The invention relates to cooling elements for injection apparatus and corresponding cooling containers.
Injection apparatus are known for example from U.S. Pat. No. 5,370,629 or are conventional syringes for administering medicines. Insulin-dependent diabetics, for example, have to be capable at any time of administering the required insulin using a syringe or injection pen. In this way, the skin is pierced by an injection needle (hereafter simply called a needle) when the insulin is injected.
The terms distal and proximal are used herein in such a way that distal means facing towards the patient and proximal means facing away from the patient.
It is known that the pain when a needle penetrates during an injection is substantially less or even absent if the skin is cooled or significantly cooled. Appropriately cooling the skin can reduce or even eliminate the pain when the needle penetrates into and under the skin.
As an example of a cooling device for anesthetizing the skin, U.S. Pat. No. 4,725,265 describes a syringe comprising a cooling device which sprays a coolant gas onto the surface of the skin before the injection is performed. The skin is only cooled before the injection, such that the effect noticeably wears off during lengthier injections. Since the application described is the injection of anesthetics, the anesthetic cancels out the wearing off of the cooling effect, which is not the case with other medicines. Furthermore, cooling this way requires a separate supply of coolant gas, such that for multiple injections a relatively large amount of coolant gas, and/or correspondingly large gas containers, are required. Another device, such as is shown in U.S. Pat. No. 5,921,963, cools the skin before and during the injection by means of a cooling plate connected to a cooling apparatus. In order to be able to use the cooling plate, the cooling apparatus must first be operated a certain period of time, a particular difficulty if the apparatus is supplied batteries for an out-patient application, especially since the batteries have a substantially lower output as compared to a mains supply. Due to its time-consuming initialization and the fact that an integrated cooling apparatus is constantly carried along with it, this structurally elaborate cooling device is also not suitable for out-patient injections performed by a non-professional.
It would be advantageous to conveniently and simply cool the skin during out-patient therapies. Ideally, the appropriate point on the skin is cooled to 12° C. or lower.